Hi,
I've successfuly bonded 2 sets of bunnys. I think its an especially good start that they've been together for such a long period of time without any major fights breaking out! You're very lucky in that it sounds like you have a clear dominant (Buzz) and a clear submissive (Jessie) as the battle for the dominant bunny position is what can cause bonding to take some time.
The mounting is competely normal, my dominant bun Timmy did that to his submissive girl Mimi a few times when they were first bonding as his way of confirming his position. It's totally fine to let this happen, aslong as Jessie is OK with it. Once he feels established as top bun, Buzz will stop doing it.
Timmy and Mimi were abit rough with eachother at first and would boss eachother around with nips and nudges, but that soon stopped aswell. They just need to get to know eachother in their own time and work out their own dynamics.
I think you're doing fab so far and will definatly be a success story in the bunny bonding stakes! I have found that once they start grooming its a pretty fast track into being able to leave them totally alone together, and before you know it it will be like they've been friends for life!
Having said that, Timmy and Mimi still have the occasional tiff, mostly in the mornings when they're anticipating their breakfast! But hey, if ur around someone enough you do have disagreements don't you?!
The only bits of advise I have for you is to make sure theres enough hay and food that they don't feel they're competing for it, and allow them some time apart to rest on their own. Bonding is stressful for them so they definatly need a break from it (as do you!) Also don't underestimate your role in it, you're overall top bunny and Buzz needs to know you'll step in if he attacks and Jessie needs to know you'll protect her if necessary. Calm encouraging talking HONESTLY goes a long way.
Let me know how it's going.
Good luck and Love to Buzz and Jessie :wave: